Mobile electronic devices, including portable audio systems such as wearable headphone devices, often distract people from their surroundings. For example, it may be difficult to get the attention of a person wearing a headphone device when the volume of the headphone device is high, or when the headphone device includes a noise cancellation feature. As a result, getting a person's attention from short distances can be difficult, and may require waving at that person, calling that person's name out, or walking up to that person to get his or her attention.